The present invention relates to a device used in the installation of an indoor sprinkler system to locate the point on a ceiling or wall where the plumbing for the sprinkler system will intersect for purposes of installation of the sprinkler head or additional plumbing. The invention allows the installer to drill a hole in the ceiling or wall knowing that the pipe for the system will always be centered within the hole and allows the installer to perform this function in significantly less time than present methods. Other less efficient methods include a plumb-bob, or a device employing a level which must be held in place until the level is found before the point can be identified. All prior methods are less accurate and more time consuming for the installer. When a sprinkler system is installed into a building which is kept at below freezing temperatures, such as a warehouse for meat or perishables or in a supermarket or distribution center, the system must be installed dry, without water. The dry system is filled with air and when the system is triggered, the air is released which triggers the water supply to send water into the system. The plumbing of the dry system must be pitched so as to allow the water to run into the system and through the sprinkler heads when needed. The present invention is very useful in installing a pitched system A dry sprinkler system is filled with air rather than water to prevent freezing. Because the plumbing lines are pitched, the one inch outlets for the drops are not plumb. So the use of a plumb-bob would be totally inaccurate and measuring the spot would be mostly guess work because the installer does not know the actual angle of the pipe. The present invention can be installed and extended to mark the point according to any degree of pitch.
The only other accurate way would be to use a piece of pipe cut to the approximate length from the outlet to the ceiling, install it, then mark the ceiling. That option can be very clumsy. Also, the lengths change as you go down the line because of the pitch, so different lengths of pipe would be needed which would be cumbersome.
A primary feature of the present invention is that it has at one end a one-inch national pipe thread (N.P.T.) male thread pipe which engages onto the one inch diameter outlet pipe and is therefore connected such that the installer has two free hands with which to mark the point. The main body assembly of the invention consists of a telescopic shaft which extends from as small as five inches to 25 inches or longer, as needed. The main body assembly has within it shaft retainers which keep the telescopic shaft aligned within the main body assembly. The point at which the point implement at the end of the telescopic shaft reaches the ceiling or wall is where the mark is made. The installer makes the mark by applying pressure to the pressure ring causing the point implement to cause an indentation in the ceiling or wall. The point implement may also contain means for a writing utensil whereby the mark is made with ink on the ceiling or wall. The installer then disconnects the device from the pipe and drills the hole. It is therefore unnecessary for the installer to create a level point or a plumb-bob point and there is no actual measurement which must be done.
The object of the invention is to provide a device which easily allows an installer to locate a point on the ceiling or wall which is accurate and which does not involve time-consuming measurement. By eliminating measurement, human error is eliminated, and therefore waste of materials and time is eliminated.